You can Google up advice on this topic--I did and here is what we did
to take care of the stain, with mixed results.

We applied white vinegar to the stain first, diluted by half with water.
Then we used an enzymatic cleaner like Nature's Miracle. That pretty
much took care of the smell, but we were left with a big black stain.
We got a big bottle of hydrogen peroxide and a giant roll of paper
towels.Wet the paper towels with the hp and lay them evenly over
the stain. Make sure the saturation is as even as possible. Leave it
there all day, take the towels up, and apply again until you have
lightened the wood to the desired color.

The hp bleaches the black out of the wood. HOWEVER, the end
result is not always as even as you might like. The great thing is, the
hp seems to penetrate any finish and bleach the wood underneath it,
if that is possible. We have a light polyurethane or somesuch finish,
a little shiny, and that spot is still shiny.

I don't know that there is any other solution save refinishing the
floor.

Good luck!

daaamn

besides the smell
you might consider sanding the whole room and staining it a shade
darker
(dark enough to blend out the stain)

just depends on how clean the rest of the floor is you know
but in the end.. it would conceal the pee stain